WASP-99 b
WASP-99 b is a hot Jupiter orbiting WASP-99 in the constellation Eridanus. It lies about 518 light-years from Earth and was discovered in 2014 using the transit method.
How Big Is WASP-99 b?
WASP-99 b has a radius of 11.43 times that of Earth, or 1.02 times the radius of Jupiter. Its mass is 772 times that of Earth.
Is WASP-99 b in the Habitable Zone?
The position of WASP-99 b relative to the habitable zone of WASP-99 cannot be precisely determined from the available orbital data.
Habitable zone of WASP-99: 1.363–3.184 AU (conservative: 1.727–3.018 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Orbit and Year Length
A year on WASP-99 b — one full orbit around WASP-99 — lasts 5.75 Earth days, shorter than Mercury's 88-day year.
How Was WASP-99 b Discovered?
WASP-99 b was discovered in 2014 using the transit method, with observations from SuperWASP.
The transit method watches a star for the tiny, regular dip in brightness that occurs when a planet crosses in front of it. The depth and timing of these dips reveal the planet's size and orbital period.
How Far Away Is WASP-99 b?
WASP-99 b is 517.5 light-years (158.7 parsecs) from Earth. Light arriving here tonight left the planet around the year 1509. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 9,108,000 years to make the journey.
Earth Similarity Index
The Earth Similarity Index (ESI) scores how physically similar a planet is to Earth, from 0 to 1, based on radius, density, escape velocity and surface temperature. WASP-99 b scores 0.08, ranking #4,699 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: WASP-99
WASP-99
- Surface temperature
- 6,150 K (Sun: 5,772 K)
- Mass
- 1.21 M☉
- Radius
- 1.64 R☉
Planetary System
WASP-99 b is the only planet known to orbit WASP-99 so far.
WASP-99 b — Complete Data
| Radius | 11.433 Earth radii (1.020 Jupiter radii) |
|---|---|
| Mass | 772.33 Earth masses (2.430 Jupiter masses) |
| Orbital period | 5.75 days |
| Earth Similarity Index | 0.08 |
| Distance from Earth | 517.5 light-years (158.7 parsecs) |
| Constellation | Eridanus |
| Discovery method | Transit |
| Discovery facility | SuperWASP |
| Discovery year | 2014 |
Data: NASA Exoplanet Archive, last updated 2018-04-25. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About WASP-99 b
Is WASP-99 b habitable?
WASP-99 b is not known to orbit within the habitable zone of WASP-99, and as a hot Jupiter it is an unlikely candidate for life as we know it.
How far away is WASP-99 b?
WASP-99 b is about 518 light-years from Earth in the constellation Eridanus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 9,108,000 years to get there.
How big is WASP-99 b compared to Earth?
WASP-99 b has 11.43 times the radius of Earth and about 772 times its mass.
How long is a year on WASP-99 b?
One orbit around WASP-99 takes 5.8 Earth days — short enough that 63 of its years would fit into one Earth year.
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